Sequential vibration preventer and vibration control structure for ball hitting implement

ABSTRACT

A sequential vibration preventer for a ball hitting implement in which impact vibration that is generated when a ball is hit is transmitted to the human body from the impact generation source via the ball hitting implement. The sequential vibration preventer is detachably mounted on a portion of the implement where the vibration amplitude is large, such as the frame shaft or grip, so that the impact vibration is attenuated, and injury to the body is prevented. A ring body consisting of a soft material that has extendability or viscoelasticity is provided, and a plurality of vibrators are sequentially embedded in the circumferential direction in a single ring configuration or in a multiple ring configuration in the interior of the ring body. Alternatively, a belt body consisting of a soft material that has extendability or viscoelasticity or of a flexible material that is non-extendable, is provided, and a plurality of vibrators are embedded in the interior of the belt body so that these vibrators are sequentially disposed in one direction in a single row or in a multiple rows. A two-sided adhesive tape is disposed on either the outer surface or inner surface of the belt body.

TECHNICAL FIELD

The present invention relates to a sequential vibration preventer in aball hitting implement, the term “ball hitting implement” referring to aball hitting implement such as a tennis racquet, soft tennis racquet,squash racquet, badminton racquet, racquet ball racquet, golf club,baseball bat or the like. Here, the present invention will be describedusing mainly a tennis racquet as an example.

BACKGROUND ART

In a tennis racquet, the vibration of the impact when the ball is hit istransmitted to the frame from the gut plane (strings) and is furthertransmitted to the body of the player, i.e., wrist, elbow, etc., fromthe grip portion via the handle portion. If the body is frequentlysubjected to such impact vibration over a long period of time, cases ofinjuries such as peritendinitis and tennis elbow are commonly seen. Fromthe incidence rate as well, this is viewed as a problem of sportsinjuries that cannot be ignored.

In the past, there have been vibration preventers that are mounted onthe gut plane, bottom surface of the grip end or interior of the frameshaft in order to alleviate impact vibration of this type; however, noimpact preventer that is detachably mounted on the outer circumferentialportion of the frame shaft has been seen.

Typical vibrations that are the greatest in the frame shaft vibrationstransmitted to the body when the ball is hit, and that have an effect onbodily injuries, include a two-node bending mode at approximately 120 Hzthat is the fundamental mode characteristic of the frame shaft, as wellas relatively higher-frequency vibrations such as a three-node bendingmode at approximately 330 Hz, a two-node twisting mode at approximately360 Hz, and a primary membrane vibrational mode of the strings atapproximately 560 Hz. Besides these vibrations, there are numerous othervibrations up to high frequencies of approximately 2000 Hz, and it isknown that respective characteristic non-vibrating parts or “nodes” areformed on the frame shaft in the main vibrational modes.

Here, the conditions of the “nodes” of the main vibrational modes areblack and white boundary line portions as shown in FIG. 9 (cited fromYoshihiko Kawazoe: Rakketo no Kagaku [Racquet Science] II—: GekkanTenisu Jaanaru (Monthly Tennis Journal), 123, pp. 76–81 (1994.1)). Theareas that are distant from these nodes are areas in which the vibrationamplitude of the frame shaft is large, and are referred to as “bellies”of vibration. Especially in regard to the fundamental vibrational modeof the racquet, it has been found that the modes that make a largecontribution to an unpleasant ball hitting sensation and injuries to thebody are the two-node and three-node bending modes. Furthermore, itwould appear that the mounting of vibration preventers in the areasforming the common “bellies” of both modes is an effective means ofabsorbing or attenuating vibration.

Furthermore, as is shown in FIG. 10, the respective implement portionsthat correspond to the racquet face portions (B1, B2, B3, B4), the frontend portion (A) of the grip and the rear end (C) of the grip (in thevicinity of the grip end) constitute “bellies” where the vibrationamplitude of the three-node bending mode that is generated in the caseof relatively high-velocity center hitting is large. Accordingly, animprovement in the ball hitting sensation during center hitting would beexpected when vibration preventers are mounted on these portions.

Furthermore, these implement portions are also common to the two-nodebending mode that is generated mainly in low-velocity hitting andoff-center hitting.

Accordingly, in light of the fact that the impact vibration caused byhitting of the ball is transmitted to the human body from the impactgenerating source via the frame shaft portion and handle portion, thepresent invention provides a sequential vibration preventer in whichimpact vibration is attenuated by mounting vibration preventers on theframe shaft that propagates such impact vibration, so that deleteriouseffects of such impact vibration on the body are prevented, and a gripvibration control structure using this sequential vibration preventer.The term “sequential vibration preventer” refers to a vibrationpreventer that has sequential or continuously lined up vibrators, and itis not a term indicating a special vibration mode for “sequentialvibration.”

DISCLOSURE OF INVENTION

The present invention is a sequential vibration preventer in which aring body or belt body consisting of a soft material that hasextendability or viscoelasticity has a plurality of sequential orcontinuously lined up vibrators and/or a plurality of rows of suchvibrators. This sequential vibration preventer is devised so that thevibrators, which are comprised of a material with a high specificgravity, are surrounded by the soft material, so that the impactvibration that occurs during the hitting of the ball is absorbed orattenuated. When this vibration preventer is used, vibration can beprevented by mounting the preventer on parts that constitute “bellies”of vibration in the ball hitting implement.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates an embodiment in which a ring body is formed, inwhich (a) is a front view and (b) is a central sectional view,respectively.

FIG. 2 illustrates an example of use of the same in a tennis racquet, inwhich (a) is a partial side view explanatory diagram and (b) is asectional explanatory diagram.

FIG. 3 is a partial side view explanatory diagram illustrating anexample of use of the same in a baseball bat, in which (a) showsvibrators with a multiple ring configuration and (b) shows vibratorswith a single ring configuration.

FIG. 4 is a partial side view explanatory diagram illustrating anexample of use of the same in a golf club, in which (a) shows themounting on the front end portion of the grip, and (b) shows themounting on the rear end of the grip.

FIG. 5 is a partial side view explanatory diagram illustrating anexample of use of an embodiment in which a belt body is formed on theshaft of a tennis racquet.

FIG. 6 is a partially cut-away sectional explanatory diagramillustrating an example of use of the same on the grip of a tennisracquet.

FIG. 7 illustrate an example of use of another embodiment equipped withplate-form vibrators that form a slit-equipped ring body, in which (a)shows a partial side view explanatory diagram and a sectionalexplanatory diagram (b).

FIG. 8 shows longitudinal sectional explanatory diagrams (a, b, c) of anembodiment in which a belt body equipped with cut grooves isconstructed, and a cross-sectional explanatory diagram (d) of FIG. 8(c), in which (a) is an embedded installation, (b) is an protrudinginstallation or semi-recessed installation, (c) shows linear orbelt-form vibrators, and (d) shows a configuration in which a pluralityof rows are installed.

FIG. 9 is an explanatory diagram that shows the respective vibrationalmodes (a, b, c, d) generated in a racquet.

FIG. 10 is an explanatory diagram which shows the positions (A, B1through B4, C) of “bellies” where the vibration amplitude that is commonto the two-node and three-node bending modes generated by the hitting ofa ball is large.

FIG. 11 is an explanatory diagram illustrating an example of use on theinside surface of the frame in the racquet face portions, with mountingon the implement portions B1 through B4 shown in FIG. 10.

The symbols used in the Figures are listed and explained below.

1: Ring body

1′: Belt body

2: Vibrators

3: Two-sided adhesive tape

4: Cut grooves

5: Cut slit

V: Grip (construction part)

W: Frame shaft (or club shaft)

X: Racquet

Y: Baseball bat

Z: Golf club

BEST MODE FOR CARRYING OUT THE INVENTION

In order to give a more detailed description of the present invention,the present invention will be described below with reference to theaccompanying drawings.

(Embodiment 1)

An embodiment in which a ring body is constructed is described asfollows with reference to FIGS. 1 and 2. In the sequential vibrationpreventer, a ring body (1) is formed from a soft material that hasextendability or viscoelasticity. A plurality of sequential orcontinuously lined up vibrators (2) are embedded in the interior of thisring body (1), and the inner circumferential surface of the ring body(1) that is caused to contact the ball hitting implement when the ringbody (1) is mounted on the ball hitting implement is formed in an archshape in cross-section.

Here, the plurality of vibrators (2) are disposed in an annularconfiguration in the radial direction in the interior of the ring body(1) and constitute a single ring or multiple ring configuration.

As is shown in the Figures, the individual adjacent vibrators do notcontact each other; but they can be viewed as being regularly disposedin a sequence, and thus they are disposed in a single row (single ringconfiguration). In the case of a plurality of rows (multiple ringconfiguration), a tubular ring body is formed, and reference should bemade to FIGS. 3 and 4 below.

Here, the disposition of the vibrators (2) does not exclude aconfiguration in which a number of vibrators are strung together. Ofcourse, the vibrators (2) are not limited to vibrators that are uniformin terms of specific gravity and volume, and the vibrators can also bedisposed in an irregular (random) disposition.

Moreover, in cases where the vibrators (2) are formed by linear bodiesor belt-form bodies, the vibrators can be disposed in a single row or ina plurality of rows (not shown in the drawings).

Furthermore, the shape of the ring body (1) can be an annular shape suchas that shown in FIG. 1 or a square frame shape such as that shown inFIG. 2; and any configuration that forms a hoop or loop is permissible.The internal diameter of the ring body (1) is set at a value that isslightly smaller than the external diameter of the frame shaft (W) ofthe racquet (X). The ring body (1) is expanded (spread in diameter),fitted over the frame shaft from the bottom portion of the grip end,moved to a specified position, and mounted (held elastically) on theframe shaft.

Here, since the inner circumferential surface of the ring body (1) isformed in an arch shape as seen in a sectional view, the tight adhesionof the ring body (1) when mounted is improved. More specifically, thering body (1) is flattened as a result of the expansion (spreading indiameter), so that the inscribed area is expanded, thus causing theelastic recovery force to act toward the inside of the ring body (1).Accordingly, the press-bonding characteristics with respect to themounting position are reinforced.

Furthermore, a strengthening of the mounting including the prevention ofslipping can be accomplished by disposing a two-sided adhesive tape onthe inner circumferential surface of the ring body (1) or by forming arecessed portion or groove (not shown in the drawings) in the shaft (W)and accommodating the ring body (1) in this recessed portion or groove.

Furthermore, as is shown in FIG. 7 which will be described later, a cutslit (5) can be formed in a portion of the ring body (1), thusconstructing the ring body (1) so that this cut slit can be opened;then, following mounting, the joining surfaces of the cut slit (5) arebonded together.

(Embodiment 2)

Another embodiment in which a ring body is constructed will be describedwith reference to FIGS. 3( a) and 4. The sequential vibration preventeris equipped with a wide (tubular) ring body (1), which is formed from asoft material that has extendability or viscoelasticity, andsequentially disposed vibrators (2) in a single ring configuration aresequentially disposed in the interior of this ring body (1) in the axialdirection so that a multiple ring configuration is obtained.

FIG. 3( a) shows an example of use in the grip (handle portion) of abaseball bat (Y); here, a preventer with a multiple ring configurationis mounted on the front end portion of the grip. Furthermore, one or aplurality of preventers with a single ring configuration may also bemounted as shown in FIG. 3( b). Moreover, a case in which the preventeris mounted close to the gripping knob on the grip end is alsoconceivable (though not shown in the drawings).

FIG. 4 shows an example of use in the grip of a golf club (Z). ThisFigure illustrates a case in which a bag-form rubber grip (V) thatincorporates and integrates two ring bodies (1) is used. In the rubbergrip (V) shown in this Figure, recessed portions are formed in theinside surface of a cylindrical member that has a bottom (these recessedportions are formed in two places in the Figure), and the ring bodies(1) are accommodated in these recessed portions, so that the shaft (W)is elastically held. Alternatively, recessed portions (or recessedgrooves) are formed in the outer circumference of the shaft (W), and thering bodies (1) are accommodated in these recessed portions or recessedgrooves (vibration control structure described in claim 9 or claim 10).Of course, there may also be use in a configuration in which a ring isfitted over an existing shaft (W) or grip (V) in the same manner as inthe case of mounting on a racquet (Embodiment 1).

(Embodiment 3)

An embodiment in which a belt body is constructed will be described withreference to FIGS. 5 and 6. Here, the vibration preventer is equippedwith a belt body (1′) formed from a soft material that has extendabilityor viscoelasticity, or a flexible material that is non-extendable. Aplurality of vibrators (2) that are sequential or continuously lined upin the direction of length are embedded in the interior of this beltbody.

FIG. 5 shows a case in which the sequential vibration preventer iswrapped in a spiral configuration about the outer circumferentialportion of the frame shaft (W) of a racquet (X) and is mounted by meansof a two-sided adhesive tape (3).

FIG. 6 shows a case in which a recessed portion is formed in a spiralconfiguration in the leather or rubber inner surface of the grip (V) ofa racquet (X), or a recessed portion is formed in a spiral configurationin the frame shaft (W) of such a racquet (X), and the belt body (1′) isaccommodated along this recessed portion.

Here, besides spherical bodies, the vibrators 2 that are used can becircular or square plate bodies (see FIG. 7), linear bodies or belt-formbodies (see FIGS. 8( c) and 8(d)), etc. Furthermore, the use of a rubberwith a high specific gravity as the material of the vibrators 2 can alsobe considered when these vibrators are used in a ring body (1).

By way of forming cut grooves (4) at predetermined intervals in thesurface of the belt body (1′) as shown in FIG. 8, the belt body (1′) caneasily be cut to the length and/or weight required by the user (from aminimum of one vibrator) using these cut grooves as a guide.

The cut grooves (4) are formed by making cut-outs in the cross-sectionaldirection through the sectional thickness between adjacent vibrators (2)in the surface on at least one side of the belt body (1′), and they aredisposed at equal intervals in the direction of length of the belt body.A two-sided adhesive tape (3) is disposed on either the outer surface orinner surface.

In the example shown in the Figures, the cut grooves (4) are formed in adirection perpendicular to the direction of length of the belt body(1′). However, there may also be cases in which the belt body is wrappedin a spiral configuration around the grip of the tennis racquet as shownin FIG. 6; accordingly, the cut grooves (4) can be respectively disposedin an oblique direction.

The vibrators (2) can be disposed in a protruding installation orhalf-sunken installation on the belt body (1′) as shown in FIG. 8( b).

Furthermore, in regard to the shape of the vibrators 2, round or squareplate bodies (see FIG. 7), linear bodies or belt-form bodies (see FIGS.8( c) and 8(d)), etc. can also be appropriately used besides sphericalbodies. Moreover, the use of a rubber with a high specific gravity asthe material of the vibrators 2 can be also considered when thesevibrators are used in a ring body (1).

(Embodiment 4)

Another embodiment in which a ring body is constructed is shown in FIG.11. Here, ring bodies are mounted on the inside surface of the frame ofa racquet face portion. The portions of the implement on which thesering bodies are mounted are B1 through B4 shown in FIG. 10, and they arethe portions where the vibration amplitude is large in the racquet faceportion. Even more preferably, the inner circumferences of the ringbodies (1) are aligned with the outer circumferential edges of theprotruding portions of the grommets, and a two-sided adhesive tape isdisposed on the side circumferential surfaces of the ring bodies (1)that contact the frame, so that the ring bodies are mounted in a mannerthat allows the gut to be strung through both holes. In this case, it isdesirable that the shape of the ring bodies (1) resemble the shape of abarnacle (which is a type of shellfish that grows on ship hulls, reefs,etc.). Here as well, the mounting characteristics including theprevention of slipping can be reinforced by forming recessed portions orrecessed grooves in the outer circumferential edges of the protrudingportions of the grommets, and press-fitting or engaging the ring bodies(1) with these recessed portions either directly (“as is”) or with atwo-sided adhesive tape interposed.

INDUSTRIAL APPLICABILITY

In the present invention, a structure is adopted in which sequentialvibrators (2) are combined and integrated with a ring body (1) or beltbody (1′) consisting of a soft material that has extendability orviscoelasticity, and the frame shaft (W) and vibrators (2) are separatedvia this soft material (1, 1′) in the mounting positions, so that theimpact vibration that occurs when a ball is hit is converted intokinetic energy by the vibration of the sequential vibrators (2) via thesoft material at different individual timings. Accordingly, the impactvibration can be effectively attenuated.

Furthermore, a major characterizing feature of the present invention isthat since vibrators (2) which are separated (disposed spacedly) areused in a ring body (1) whose material is a soft material that hasextendability or viscoelasticity, the vibration preventer is free toundergo extension and contraction or deformation, and mounting of thevibration preventer in conformity to curved shapes in different mountingpositions is easily done.

Moreover, the ring body (1) is constructed from a soft material that hasextendability, and it can be mounted in specified positions by expandingthe ring body; accordingly, the vibration preventer will not beseparated by impact form a ball hitting implement.

Furthermore, the mounting characteristics including the prevention ofslipping can be enhanced with a two-sided adhesive tape (3) disposed onthe inner circumferential surface of the ring body (1) or on either theouter surface or inner surface of the belt body (1′).

The ring body (1) or belt body (1′) as a whole can be prepared as aneasy-to-carry attachment (accessory) and is convenient in thatanti-vibration characteristics can easily be provided by a simplemounting operation. Accordingly, the present invention has a highutilization value in the industry.

1. A vibration preventer for a ball hitting implement comprising: a beltbody (1′) consisting of a material selected from the group consisting ofa soft material that has extendability or viscoelasticity and a flexiblematerial that is non-extendable; a plurality of vibration dampeners (2)integrated into said belt body (1′) by being embedded, contained,sunken, half-sunken or caused to protrude in an interior or on a bodysurface of said belt body (1′) so that the vibration dampeners (2) arelined up in a direction of length of the belt body; cut grooves (4)formed by cut-outs in a cross-sectional direction through a sectionalthickness of the belt body (1′) in a surface on at least one side ofsaid belt body (1′) and lined up at equal intervals in a direction oflength of the belt body (1′); and a two-sided adhesive tape (3) disposedon at least one of an outer surface or an inner surface of the belt body(1′).
 2. The vibration preventer for a ball hitting implement accordingto claim 1, wherein a plurality of vibration dampeners (2) are disposedin at least a single row in a direction of length of the belt body (1′).3. The vibration preventer for a ball hitting implement according to anyone of claims 1, and 2, which is characterized in that the shape of thevibration dampeners (2) is one selected from the group consisting ofspheres, circular plates, cubes, rectangular solids, plate bodies,linear bodies and belt-form bodies.
 4. A vibration control structure fora ball hitting implement that uses the sequential vibration preventeraccording to claim 2, wherein said vibration control structure comprisesa recess formed in portions of the implement where vibration amplitudeis large when a ball is hit; and said vibration preventer of claim 2 ispress-fitted or engaged in the recess directly or with a two-sidedadhesive tape interposed.
 5. A vibration control structure for a gripportion of a ball hitting implement, the vibration control structurecomprising the vibration preventer according to claim 2 mounted on agrip portion of a shaft of the ball hitting implement, a covering with agrip made from rubber or leather provided on an outer circumference ofthe vibration preventer of claim 2, and a recess formed in an outercircumference of said shaft or in an inside surface of the grip, andwherein said vibration preventer is accommodated in said recess.
 6. Avibration control structure for a ball hitting implement that uses thesequential vibration preventer according to claim 3, wherein saidvibration control structure comprises a recess formed in portions of theimplement where vibration amplitude is large when a ball is hit; andsaid vibration preventer of claim 3 is press-fitted or engaged in therecess directly or with a two-sided adhesive tape interposed.
 7. Avibration control structure for a grip portion of a ball hittingimplement, the vibration control structure comprising the vibrationpreventer according to claim 3 mounted on a grip portion of a shaft ofthe ball hitting implement, a covering with a grip made from rubber orleather provided on an outer circumference of the vibration preventer ofclaim 3, and a recess formed in an outer circumference of said shaft orin an inside surface of the grip, and wherein said vibration preventeris accommodated in said recess.
 8. A vibration control structure for aball hitting implement that uses the sequential vibration preventeraccording to claim 1, wherein said vibration control structurecomprises: a recess formed in portions of the implement where vibrationamplitude is large when a ball is hit; said vibration preventer of claim1 is press-fitted or engaged in the recess directly or with a two-sidedadhesive tape interposed.
 9. A vibration control structure for a gripportion of a ball hitting implement, the vibration control structurecomprising: the vibration preventer according to claim 1 mounted on agrip portion of a shaft of the ball hitting implement, a covering with agrip made from rubber or leather provided on an outer circumference ofthe vibration preventer of claim 1, and a recess formed in an outercircumference of said shaft or in an inside surface of the grip, andwherein said vibration preventer is accommodated in said recess.